Here's a quick summary of President Obama's latest campaign trip: Six battleground states, 39 hours, quite a few cups of coffee and it's not over yet.

Mr. Obama is about two-thirds of the way through a cross-country barnstorming tour. Right now, he's off to Virginia after holding an event in Florida earlier this morning. Florida's a state, of course, that knows something about razor-close elections. Here's NPR's Scott Horsley.

SCOTT HORSLEY, BYLINE: Florida is the fourth stop on what the president jokingly calls his marathon campaign extravaganza. In the last 24 hours, he's also held rallies in Davenport, Iowa; Las Vegas, Nevada; and before a screaming crowd of 16,000 in Denver, Colorado.

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HORSLEY: Throughout this trip, the president is drawing contrast between his agenda and Republican rival Mitt Romney's, just as he has for months. But with the election now just 12 days away, Mr. Obama's adding a more direct appeal as he tries to close the sale.

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HORSLEY: Polls show a close race nationally, and in almost every one of the battleground states. So neither party can afford to leave any potential votes on the sidelines. That's the message of a new Obama campaign ad inspired by the 2000 presidential race in Florida.

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HORSLEY: That message is especially important for the president, whose strategy depends on expanding the voter base and mobilizing people who don't automatically show up to vote in every election, including young people, African-Americans and Latinos.

From Air Force One yesterday, Mr. Obama telephoned dozens of radio disc jockeys, most of them African-American, urging them to remind their listeners to vote. Later, he appeared on the "Tonight Show," where he told Jay Leno he'll be casting his own vote in Chicago later today.

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HORSLEY: Early voting is an important part of the Obama strategy, since it makes voting easier for people who might not get to the polls on November 6th.

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HORSLEY: Denver Mayor Michael Hancock wasted no time after last night's rally trying to get the president's supporters to the polls.

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HORSLEY: Colorado Governor John Hickenlooper went a step further, telling the president's supporters not to let up after casting their own votes, but to keep dragging their friends to the polls.

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HORSLEY: The Obama team insists this grind-it-out, vote-by-vote contest is what they always expected, and what they've spent more than a year preparing for. Mr. Obama joked yesterday about pulling an all-nighter on this campaign trip. There could be 13 more long nights ahead.